For an explanation of why and how to assess environmental and route conditions, read this post. You will notice that the assessment below does not contain every possible detail, since this was a relatively straightforward trip in familiar terrain during a friendly time of year. If the trip had been longer in duration or distance, had bigger risks or more variability, or presented a new environment or season, I would have done a more exhaustive assessment.

Climate

For the month of June, average temperatures in Yosemite Valley are:

Average high: 73 F

Average low: 42 F

The weather station in Yosemite Valley is at an elevation of 4,018 feet. Our route is generally between 7,000-8,000 feet, which equates to a 9-12 degree temperature difference. Therefore, if we experience average conditions, we should expect:

In the month of June, Yosemite Valley on average sees 1.48 inches of precipitation.

Our route receives more precipitation, since it’s higher and colder. But, even if precip is 2x, that’s only 3 inches, which makes precip during our trip possible but unlikely. If there is precip, it is probably a nasty late-winter storm with a mix of rain and snow — let’s hope we avoid one.

Footing

We will be hiking primarily on trail. The trail is a mix of dusty dirt, rock, and rock slabs.

When we hike off-trail, the footing will be mostly the same, though there should be less dust and loose rocks.

Source: Photos geotagged near our route (viewable in Google Maps)

Vegetation

Our route is mostly in the Upper Montane Forest, which in Yosemite is generally between 6,000 and 8,000 vertical feet.

Red firs and Ponderosa pines will tower above us, while the forest floor will be relatively free of vegetation, save for pockets of scratchy chapparel. There will be many sunny overlooks and gaps in the tree cover, especially when hiking on granite slabs.

When hiking off-trail through chapparel, pants are recommended.

Good campsites (i.e. protected, soft, good drainage, flat, and free of undergrowth) should be easy to find.

Water availability

There should be plenty of water, as the route follows and crosses many streams and side-streams. Some of these sources are seasonal, but since the winter snow just recently melted off they should be full.

Problematic wildlife

Black bears are a chronic problem in Yosemite, especially at popular backcountry campsites. In fact, the Park Service requires that all backcountry users store their food in bear-resistant containers.

In addition to the bears, there are also problems of “mini bears” at popular campsites. Raccoons, squirrels, rabbits, etc. are almost as good as bears in stealing food and chewing apart salty gear (e.g. shoulder straps, trekking pole grips, etc.)

Insects

Mosquitoes in Yosemite can be pretty bad. Not Alaska bad, but bad, definitely enough to warrant full-coverage clothing and a headnet during peak season.

Usually the bugs are worst shortly after the snow melts off, when there are ample puddles of snowmelt for them to breed and once temperatures are warm enough. Once the puddles evaporate or drain off, the bugs subside, though they continue to be a nuisance near perennial water sources.

The snow melted off our route just recently; in fact, we may still encounter a few lingering patches on north-facing and leeward slopes. So, it is possible that we will be there for the first hatch. Yeehaw!

Natural hazards

There are overlooks of Yosemite Valley along the route that are surrounded by vertical cliffs. Beware here!

We will be crossing Yosemite Creek, which at this time of year is swollen with snowmelt. However, this past winter was a low snow year and its flow should be less than average. Plus, there’s a bridge over the creek just upstream of Yosemite Falls.

We will not be in any avalanche terrain.

Source: topo maps, Brian Robinson, SNOTEL data

Remoteness

We are starting from a popular trailhead and using popular trails. However, do not expect cell reception, even along the rim of Yosemite Valley (where there is a cell tower).

2 Responses to Sample: Environmental and Route Condition Assessment

I wish to thank you for having this site. I have never been to Yosemite, as was wondering the conditions so I could pack accordingly for an off trail 3-6 day hike.

I need to digest more of you site.

I see you have the Sierra High Route Mapset. Does that include Yosemite Valley?

My trip is going to be something like
Day 1 – Yosemite Valley
Day 2 – Halfdome at sunup, to Sunrise Lake if I can get a permit, or where ever.
Day 3 – North Dome, Yosemite Falls if I can do that in a day.
Day 4 – Slip out and thumb a ride to my rental car
Day 5 – I’d like to do a little more while I’m there, seeing seeing I live in Raleigh, NC.
Any suggestions.

I’m thinking of your week trip, Yosemite B or C, but wanted to see the falls with more water than in September, or is that not an issue? I was thinking April/June timeframe. I’m not afraid of cold or snow, but I don’t want to have to bring crampons either if I don’t have to.

And seeing I can’t, at this time, find a hiking buddy to venture with me all the way to Yosemite, this will most likely be a solo trip.

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About Skurka

Andrew Skurka is an accomplished adventure athlete, speaker, guide, and writer. The 35-year-old is most well known for his solo long-distance backpacking trips. He is the author of The Ultimate Hiker's Gear Guide.